Immunologic adjuvant refers to a substance which can non-specifically change or enhance the specific immune response of an organism to an antigen, and it is required to be non-cancerogenic, nontoxic, high-purity, degradable, of certain adsorbability and stable. The action principle of the immunologic adjuvant is mainly represented in the following three aspects: 1) increasing surface area of an antigen to improve the immunogenicity thereof; 2) playing slow-release function to the antigen to extend the retention time of the antigen in tissue; 3) promoting inflammatory reaction to stimulate active immune response. That is to say, the immunologic adjuvant causes the immune system to recognize the immunologic adjuvant itself also as an antigen, mainly by pseudomorphically pre-stimulating the immune system, and thus can cause a behavior of immune response of the organism more early. Currently, the common immunologic adjuvant comprises aluminium adjuvant, freund's adjuvant, CpG DNA adjuvant, nanoadjuvant, microorganism and the metabolite adjuvants thereof, and the like, wherein the activity of the freund's adjuvant is far higher than those of other types of adjuvants, however, the initiated side effect thereof is too intense, and thus cannot be widely used. Aluminium adjuvant is the only immunologic adjuvant currently approved to be used in human vaccine, which is used in various liquid vaccines. However, the aluminium adjuvant can only initiate humoral immunity, but cannot induce cell immunity, which increases limitation for its application. Moreover, the bonding capacity of the aluminium adjuvant with an antigen is not stable enough, and thus the potential toxic side effect of liquid aluminium element in vaccine after injecting in large dose also draws attention. Therefore, it has become an important task in the field of contemporary immunology research to find an efficient, secure, novel immunologic adjuvant.
Traditional Chinese medicine is an important part of the traditional medical theory of our country, which has its unique theoretical system and application form. Modern research shows that some of the active ingredients in the Traditional Chinese medicines (such as saponins, polysaccharides, flavonoids, etc.) possess good immunomodulatory effects. It is reported that: ginsenosides contained in ginseng, a traditional tonic Traditional Chinese medicine, can increase the activity of macrophages induce the generation of interferon, and stimulate the activity of cytotoxic T lymphocyte; astragalus polysaccharide can produce antagonism to some immunosuppressive drugs; icariin, as a main active ingredient of total flavonoids of herba epimedii, can increases the quality of immune organs, which makes the formation rate of E rosette and serum tumor necrosis factor-α level be significantly increased. Generally, the Traditional Chinese medicines are natural products, which have high bioaffinity, and the effects thereof are mild and persistent, therefore, their advantages, as novel vaccine adjuvants, are very significant, and thus they have drawn increasing attentions.
Currently, the vaccines containing adjuvants of Traditional Chinese medicines or Traditional Chinese medicinal ingredients have been developed and exploited to some extent. However, the vaccine itself which contains an adjuvant of Traditional Chinese medicine or Traditional Chinese medicinal ingredient has problems of non-ideal effect and inconvenient use. Therefore, there is a need for an efficient, convenient vaccine injection.